An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters.

AIM: To assess a novel method for automatic in-line detection of clinical mastitis. METHODS: For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teat cups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alternative 'gold standards' for diagnosing clinical mastitis. RESULTS: In the pilot trial, 12-14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0. CONCLUSION: The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.

Rapid enzyme immunoassay for measurement of bovine progesterone.

Reproductive management is a primary financial concern of the dairy industry with missed estrus detection one of the major causes of lost income. A rapid enzyme immunoassay (EIA) was developed for on-line measurement of progesterone in bovine milk with a biosensor for detection of estrus. The EIA was developed using covalent binding microtiter wells, monoclonal antibody, horseradish peroxidase, and 3,3',5,5'-tetramethylbenzidine (TMB). The EIA took 8 min and had a dynamic response for progesterone in buffer and milk between 0.2 and 20 ng/ml.

Biosensor for on-line measurement of bovine progesterone during milking.

Reproductive management is a major financial concern of the dairy industry, with missed estrus detection a main cause of lost income. A biosensor was developed for on-line measurement of progesterone in bovine milk and detection of estrus. The biosensor used an enzyme immunoassay format for molecular recognition, which was developed to run in approximately eight minutes. The sensor was designed to operate on-line in a dairy parlor using microinjection pumps and valves for fluid transport, fiber optics and photodiodes for light measurement, and a control computer for sequencing. Calibration showed a dynamic response between 0.1 and 5 ng/ml progesterone in milk. The reusability of the test well was evaluated. Thiocyanate (0.5 M, pH 5.1) quickly regenerated the antibody surface while maintaining antibody activity for 15-20 cycles, but noise from the residual enzyme limited reusability.